Transmission characteristics of photonic crystal waveguides with stubs and their application to optical filters

We study the transmission characteristics of a photonic crystal waveguide with a single stub of a finite length and propose a double-stub waveguide structure for its application to optical filters. The proposed device operates as a Fabry-Perot interferometer and can be used as a broad bandstop filter and a narrow bandpass filter. These filters are inherently compact and their center frequency is given by the resonant frequency of the stub.